1. Field of the Invention
The present disclosure relates to cooling systems, and more particularly to a dehumidifying apparatus configured to be operable to condition air within a data center, and related methods for cooling or treating air within a data center.
2. Discussion of Related Art
Equipment enclosures or racks for housing electronic equipment, such as data processing, networking and telecommunications equipment, have been used for many years. Such racks are used to contain and to arrange the equipment in small wiring closets as well as equipment rooms and large data centers. In certain embodiments, an equipment rack can be an open configuration and can be housed within a rack enclosure, although the enclosure may be included when referring to a rack. Over the years, a number of different standards have been developed to enable equipment manufacturers to design rack mountable equipment that can be mounted in standard racks manufactured by different manufacturers. A standard rack typically includes front mounting rails to which multiple units of electronic equipment, such as servers and CPUs, are mounted and stacked vertically within the rack. An exemplary industry standard rack is approximately six to six-and-a-half feet high, by about twenty-four inches wide, and about forty inches deep. Such a rack is commonly referred to as a “nineteen inch” rack, as defined by the Electronics Industries Association's EIA-310-D standard. With the proliferation of the Internet, it is not uncommon for a data center to contain hundreds of these racks. Further, with the ever decreasing size of computer equipment, and in particular, computer servers and blades, the number of electrical devices mounted in each rack has been increasing, raising concerns about adequately cooling the equipment.
Heat produced by rack-mounted equipment can have adverse effects on the performance, reliability and useful life of the equipment components. In particular, rack-mounted equipment, housed within an enclosure, may be vulnerable to heat build-up and hot spots produced within the confines of the enclosure during operation. The amount of heat generated by a rack of equipment is dependent on the amount of electrical power drawn by equipment in the rack during operation. In addition, users of electronic equipment may add, remove, and rearrange rack-mounted components as their needs change and new needs develop.
Previously, in certain configurations, in addition to a facility cooling system that is part of the data center's infrastructure, a data center may be further cooled by employing one or more computer room air conditioner (“CRAC”) units that are typically hard piped, immobile units positioned around the periphery of the data center room. These CRAC units may intake air from the fronts of the units and output cooler air upwardly toward the ceiling of the data center room. In other embodiments, the CRAC units intake air from near the ceiling of the data center room and discharge cooler air under a raised floor for delivery to the fronts of the equipment racks. In general, such CRAC units intake room temperature air (at about 72° F.) and discharge cold air (at about 55° F.), which is blown into the data center room and mixed with the room temperature air at or near the equipment racks.
The rack-mounted equipment typically cools itself by drawing air along a front side or air inlet side of a rack, drawing the air through its components, and subsequently exhausting the air from a rear or vent side of the rack. A disadvantage of the CRAC-type of air conditioning system is that cool air is mixed with the room temperature air, which is inefficient. Ideally, to make the system as efficient as possible, and to utilize as little energy and floor space as possible, the highest possible temperature air should be drawn into the CRAC units and the outlet air generated by the CRAC should be a few degrees below room temperature. Another disadvantage of employing CRAC-type units is that, while they are particularly suited to addressing sensible cooling, such units are not particularly suited to addressing latent cooling.
Another approach is by employing computer room air handler (“CRAH”) units that are typically hard piped to a dedicated chiller plant. A trend emerging in the data center room cooling industry is the adoption of operating chiller plants with warmer supply set points, which increases the sensible heat ratio of conventional CRAH units and greatly reduces the moisture removal capacity of the unit. Traditionally, chilled water is delivered to air handlers at a temperature of 42° F. to 46° F. In an effort to promote more efficient chiller operation and higher sensible heat ratios, data center designers are presently setting chilled water supplies at higher water temperatures, e.g., water temperatures from 48° F. to 52° F.